Short-term effects of sheep excrement on carbon dioxide, nitrous oxide and methane fluxes in typical grassland of Inner Mongolia

Excrement patches of grazing animals play an important role in greenhouse gas (GHG) fluxes due to the high nitrogen (N) and available carbon (C) deposited in small areas, but little information is available for the effect of excrement in the Inner Mongolian grassland (43 26 degrees N, 116 degrees 40'E). To elucidate the effect of grazing sheep urine, fresh dung and compost on fluxes of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O), a short-term field study (65 days) was carried out in the typical grassland of Inner Mongolia with the optimised closed chamber/GC technique. Compared with the control, cumulative net CH4 consumption decreased 36, 31, and 18% from urine, fresh dung, and compost plots, respectively; net CO2-C output increased by 6.5, 1.5, and 1.2% from urine, fresh dung, and compost treated soil, respectively; about three times as much N2O-N was emitted from urine and the fresh dung treatments during 65 days. Nitrous oxide emission was positively correlated with CO, emission (R = 0.691, P < 0.01) and water-filled pore space (R = 0.698, P < 0.01). The percentages of N2O-N loss of applied-N were 0.44 and 1.05% for urine and fresh dung, respectively. Our results suggest that in autumn in the degraded grassland of Inner Mongolia, the effect of sheep excrement may be ignored when evaluating the total GHG emissions.

污泥处理经济评价和污泥堆肥中氧气监测与动态分析

With the continually increase both in the amount of wastewater disposal and in the treatment rate, more and more sewage sludge has been produced. An economic estimate was taken on the different sewage sludge disposal and treatment technologies, and led to the conclusion that compost is an effective way to make sewage sludge harmless, stable and resourceable. Normally, there are several ways to treat sewage sludge, such as landfill, compost, incineration and so on. These technologies will cost 300-1000 Y per ton of sludge. Among those ways, landfill is the cheapest one and operates easily, however, it just postpones the pollution instead of eventually eliminating the pollution; The amount of the sludge will reduce dramatically after incineration, while incineration will take a very high investment in the beginning, at the same time, it's very hard to maintain running; Sewage sludge will be resourceful after composting treantment, thus makes up the treatment cost, makes composting is the most economical way. Compost production is safe when correctly used, compost is a important way to treat sewage sludge. Oxygen is an important control factor in aerobic composting that has great effects on temperature and microorganisms. The gas gathering and transfering system of an online oxygen monitoring system for composting were bettermented to prolong the monitoring system's running period. The oxygen concentration changes in various aerobic composting stage were studied, and conclusions came to that oxygen concentration changes much faster in the oxygen concentration increasing stage than that in the declining stage; the better the aerobic condition is, the sooner the monitoring system starts to work. The minimal oxygen concentration during a ventilation cycle often falls at the beginning, then ascends in the composting period; at the same time, oxygen concentration changes fast in the early composting stage(temperature increasing stage), much slower in the middle stage(continouns thermophilic stage),and seldom changes in the late composting stage(temperature declining stage). With the help of the oxygen realtime-online monitoring system, oxygen concentrations was measured. During the composting period, water contents was analyzed after sampled. It's found that water contents (WC) and Oxygen concentration can both influence the composting process, and the control rule varies in the various composting stages. Essentially, the rule that water and oxygen control the composting process comes from water counterchecks the oxygen transferring to the composting substrate. The most influential factor to the WC and to the oxygen is the components in the composting pile. In the temperature increasing stage, seldom microorganisms exist in the composting pile with low activity, thus oxygen can meet with microorganisms' need, and WC is the dominant factor. In the high temperature (continouns thermophilic) stage, composting process is controlled by WC and oxygen, essentially by WC, at the same time, their influence somehow is not remarkable. In the temperature declining stage, WC and oxygen influence the composting process little. It's also found that the composting process will differ even if under the same components, thus to equably mix the components can avoid WC focusing in some place and let the composting pile to be aerobic. In one sentence, aerobic state is the most important factor in the composting process, suitable bulking material will be useful to the composting control.

The treatment of landfill leachate using natural systems

Leachate may be defined as any liquid percolating through deposited waste and emitted from or contained within a landfill. If leachate migrates from a site it may pose a severe threat to the surrounding environment. Increasingly stringent environmental legislation both at European level and national level (Republic of Ireland) regarding the operation of landfill sites, control of associated emissions, as well as requirements for restoration and aftercare management (up to 30 years) has prompted research for this project into the design and development of a low cost, low maintenance, low technology trial system to treat landfill leachate at Kinsale Road Landfill Site, located on the outskirts of Cork city. A trial leachate treatment plant was constructed consisting of 14 separate treatment units (10 open top cylindrical cells [Ø 1.8 m x 2.0 high] and four reed beds [5.0m x 5.0m x 1.0m]) incorporating various alternative natural treatment processes including reed beds (vertical flow [VF] and horizontal flow [HF]), grass treatment planes, compost units, timber chip units, compost-timber chip units, stratified sand filters and willow treatment plots. High treatment efficiencies were achieved in units operating in sequence containing compost and timber chip media, vertical flow reed beds and grass treatment planes. Pollutant load removal rates of 99% for NH4, 84% for BOD5, 46% for COD, 63% for suspended solids, 94% for iron and 98% for manganese were recorded in the final effluent of successfully operated sequences at irrigation rates of 945 l/m2/day in the cylindrical cells and 96 l/m2/day in the VF reed beds and grass treatment planes. Almost total pathogen removal (E. coli) occurred in the final effluent of the same sequence. Denitrification rates of 37% were achieved for a limited period. A draft, up-scaled leachate treatment plant is presented, based on treatment performance of the trial plant.

Efecto de la aplicación de abonos orgánicos sobre las características físico-químicas y microbiológicas de suelos bajo cultivo de vid de la provincia de Mendoza

El efecto de los abonos orgánicos sobre las características químicas y microbiológicas del suelo depende del cultivo, tipo de abono, dosis, frecuencia y forma de aplicación. En el caso de la vid, algunos estudios sobre la aplicación de abonos orgánicos (AAO) han reportado incrementos en los nutrientes del suelo y planta. Considerando la escasa información sobre el manejo de compost y vermicompost en suelos de viñedos de Mendoza, el objetivo de esta tesis fue evaluar el efecto de abonos orgánicos en algunas características del suelo y del cultivo. Para ello, en un viñedo ubicado en Mendoza se evaluaron los efectos de una y dos aplicaciones, superficial y enterrada, de compost y vermicompost sobre las características químicas y microbiológicas del suelo, crecimiento y rendimiento de la vid. La duración del ensayo fue de 2 años y la dosis anual fue 8 Mg ha-1. Luego de 360 días, todos los microorganismos evaluados fueron afectados por la AAO. El número de microorganismos celulolíticos fue mayor en las parcelas que recibieron compost (3,08 log10UFC g-1) que en aquellas que recibieron vermicompost (2,66 log10UFC g-1). También fue mayor cuando la aplicación fue superficial (3,07 log10UFC g-1) que cuando fue enterrada (2,67 log10UFC g-1), independientemente del tipo de abono. La AAO no afectó la salinidad del suelo. El fósforo disponible y potasio intercambiable incrementaron 237 por ciento y 28 por ciento en suelos abonados respecto de suelos al inicio del ensayo. El contenido de potasio total en pecíolo incrementó 15 por ciento en parcelas que recibieron abono orgánico respecto de las que no recibieron. La AAO en suelos de regadío de la zona árida de Mendoza se considera una alternativa promisoria por su impacto en algunas poblaciones microbianas, su efecto sobre el contenido de nutrientes en suelo y propiedades que hacen a la salinidad edáfica.

Phitotoxicity of Crhomium over Phaseolus vulgaris L.

p.75-80

Cambios en la biodisponibilidad de cromo en un suelo inducidos por la incorporación de materia orgánica

p.145-151

Producción hortícola : evolución del carbono orgánico edáfico de un argiudol típico con agregado de enmiendas

p.231-236

Incidencia de la suplementación lumínica y el uso de una enmienda de bajo impacto ambiental sobre la producción y calidad de lechuga (Lactuca sativa)

p.63-67

Phitotoxicity of Crhomium over Phaseolus vulgaris L.

p.75-80

Naturaleza de la fertilización y calidad de hortalizas

p.123-134

A Fabry-Perot Refractometer for Chemical Vapor Sensing by Solid-Phase Microextraction

The contour lithography method [1] is used to improve the fabrication yield of previously demonstrated [2] microfluidic Fabry-Perot (FP) refractive index (RI) sensors. The sensors are then coated with polydimethylsiloxane (PDMS) based polymers to detect vapor analytes by solid-phase microextraction (SPME). Preliminary characterization of devices coated with two different polymers and exposed to xylenes vapors yields a maximum sensitivity of 0.015 nm/ppm and a detection limit below 120 ppm.

Relationship between rooting behaviour and foraging in growing pigs

The objective of the present study was to investigate the relationship between rooting behaviour and foraging in growing pigs. In study 1, forty-eight 11-week-old pigs were housed in eight groups of six with access to a rooting substrate in the form of spent mushroom compost. In half of the groups the rooting substrate contained food rewards, and in the other half of the groups it did not. All pigs had ad libitum access to feed. In study 2, one hundred and ninety-two 11-week-old pigs were housed in thirty-two groups of six, all with access to spent mushroom compost, and eight groups were each fed to 70, 80, 90 or 100% appetite. Treatments were applied over a two-week period in both studies. The number of pigs involved in active rooting (rooting in substrate while standing), inactive rooting (rooting in substrate while sitting or lying) or non-rooting activity (standing in substrate area and involved in any activity except rooting) was recorded by scan sampling. These behaviours tended to reach a peak in the morning and again in the afternoon. Inactive rooting was not significantly affected by treatments in study I or study 2. Food rewards in the rooting substrate led to a significant reduction in active rooting behaviour and in non-rooting activity during peak periods of the day (P

Novel bioassays to examine the host-finding ability of plant-parasitic nematodes

We present two novel bioassays to be used in the examination of plant-parasitic nematode host-finding ability. The host-finding 'pipette-bulb assay' was constructed from modelled Pasteur pipette bulbs and connecting barrels using parafilm fastenings. This assay examines the direction of second-stage juvenile (J2) migration in response to a host seedling, through a moistened sand substrate, which underlies terminal upward-facing 'seedling bulbs', one containing a host seedling in potting compost, the other with only potting compost. An equal watering regime through both upward-facing seedling bulbs creates a directional concentration gradient of host diffusate chemotactic factors. Positive chemotactic stimuli cause the J2 to orientate and migrate towards the host plant. We present validation data collected from assays of the root-knot nematode, Meloidogyne incognita, and the potato cyst nematode, Globodera pallida, which indicate a highly significant positive attraction of J2 of both species to respective host plants. This represents a simple, quick and inexpensive method of assessing host-finding behaviour in the laboratory. We consider that the pipette-bulb assay improves on previous host-finding/chemo-attraction assays through creating a more biologically relevant environment for experimental J2; analysis is quick and easy, allowing the straightforward interpretation of results. In addition, we have developed an 'agar trough' sensory assay variant which we believe can be used rapidly to ratify nematode responses to chemical gustatory or olfactory cues. This was constructed from a water agar substrate such that two counting wells were connected by a raised central trough, all flooded with water. Two small water agar plugs were dehydrated briefly in an oven and then hydrated in either an attractant, repellent or water control; these plugs were then placed in the terminal counting wells and subsequently leached the attractant or repellent to form a concentration gradient along the central trough, which contained the initial J2 innoculum. Our data show that both M. incognita and G. pallida J2 are positively attracted to host diffusates. In addition, they displayed a strong repulsion in response to 1 M NaCl2. J2 of M. incognita displayed a mild aversion to a non-host oak root diffusate, whereas G. pallida J2 displayed a strong aversion to the same non-host diffusate; neither species responded to a compost leachate. We believe that the agar trough assay improves on previous methods by facilitating rapid diffusion of attractant or repellents. Both of the aforementioned assays were designed as tools to assess the impact of RNAi-based reverse genetics screens for gene targets involved in chemosensory orientation.

Arsenic and selenium mobilisation from organic matter treated mine spoil with and without inorganic fertilisation

Organic matter amendments are applied to contaminated soil to provide a better habitat for revegetation and remediation, and olive mill waste compost (OMWC) has been described as a promising material for this aim. We report here the results of an incubation experiment carried out in flooded conditions to study its influence in As and metal solubility in a trace elements contaminated soil. NPK fertilisation and especially organic amendment application resulted in increased As, Se and Cu concentrations in pore water. Independent of the amendment, dimethylarsenic acid (DMA) was the most abundant As species in solution. The application of OMWC increased pore water dissolved organic-carbon (DOC) concentrations, which may explain the observed mobilisation of As, Cu and Se; phosphate added in NPK could also be in part responsible of the mobilisation caused in As. Therefore, the application of soil amendments in mine soils may be particularly problematic in flooded systems. (C) 2012 Elsevier Ltd. All rights reserved.